Anchoring device



j n. 21, 1965 A. DURGET 3,224,202

ANCHORING DEVI GE Filed May 16, 1962 Sheets-Sheet 1 FIG] Deb. 21, 1965A. DURGET 3,224,202

ANGHORING DEVICE Filed May 16, 1962 ZShGBbS-SIIGG; 2

United States Patent 3,224,202 ANCHORING DEVICE Andr Durget, Paris,France, assignor to Anciens Etablissements Goldenberg & Cie, Saverne,Bas-Rhin, France Filed May 16, 1962, Ser. No. 195,291 Claims priority,application France, May 23, 1961, 862,583, Patent 1,297,817 2 Claims.(Cl. 61-45) The present invention relates to anchoring such as thatemployed in mines for supporting roofs and strengthening the facings ofgalleries.

According to known techniques for achieving the above, a boring is madein the ground and an anchoring device provided with an expanding head isinserted therein and fastened to the walls of the bore. The expansion ofthis head is controlled by a rod extending out of the bore and bearingagainst a metal anchoring plate which bears against the face of theground. This face is most often irregular in shape and it is diflicultto achieve a sound contact between the face and the anchoring plate andyet the quality of this contact affects the efiiciency of the anchoring,since it is through the anchoring plate that the applied pressure istransmitted to the ground. An insufficient contact is manifested by abad distribution of the pressure which can reach very high local values.These cause the rocks of the ground to break up and this renders theanchoring uncertain.

An object of the invention is to remedy this drawback and to this end,invention provides a method of mounting anchoring devices in the ground,said method comprising interposing between the face of the ground inwhich the anchoring device is inserted and the anchoring plate againstwhich said device bears, a coherent and deformable layer of anincompressible granular material which conforms to the shape of saidface.

With this method a perfect contact is obtained in all cases,irrespective of the shape of the face, between the anchoring plate andsaid face. The layer of incompressible material forms a filling whichmolds itself to the face of the bore while insuring, due to its verynature, a full and uniform transmission of the pressure exerted by theanchoring device.

The granular material employed to form this layer is advantageously sandagglomerated by any suitable binder. This layer can be placed inposition when anchoring or previously provided on the anchoring plateitself. Thus, according to another feature of the invention, the latterprovides an anchoring plate having on the face thereof adapted to comein contact with the ground a coherent and deformable layer of anincompressible granular material molded on the plate.-

Further features and advantages of the invention will become apparentfrom the ensuing description, with reference to the accompanyingdrawings to which the invention is in no way limited.

In the drawings:

FIG. 1 is a diagrammatic cross-sectional view of a mine gallery shown asan illustration of an anchoring method according to the invention;

FIG. 2 is a view similar to FIG. 1 on an enlarged scale of a detail ofFIG. 1 illustrating one manner of carrying out the method of theinvention;

FIG. 3 is an axial sectional view of a plate provided with a fillinglayer according to the invention;

FIG. 4 is a view of the plate shown in FIG. 3 in service, and

FIGS. 5-8 are views similar to FIG. 4 of four modifications of the plateaccording to the invention.

FIG. 1 shows a mine gallery 1 having a roof 2 in which are providedbores 3 through soft layers 4 of the ground so as to reach a hard layer5. An anchoring device A is inserted in each of these bores. This devicecomprises an expanding head 6 that a rod 7 causes to expand when it issubjected to a tractive force by a nut 8 which is threadedly engaged onits outer screwthreaded end. To achieve this traction the nut 8 bearsagainst a saucershaped plate P through which extends the rod 7 and whichbears against the face of the bore. The head 6 thus fastens itself intothe hard layer of the ground and the anchoring device supports thesubjacent soft layers. This method is known as a suspended roof supportor roof bolting. Its efliciency depends on obtaining a satisfactorycontact between the plates P and the roof 2 constituting the face of thebores 3. Now, this roof has an irregular profile and it is diflicult toobtain a satisfactory support for the plates P. To overcome thisdifiiculty there is inserted according to the invention between eachplate P and the face of the corresponding bore a filling layer C whichis best seen in FIG. 2. This layer C rests on the face of the plate P,in the presently-described embodiment in the form of a cup, and has anaxial hole 9 in vertical alignment with the hole 10 in the plate P forthe passage of the rod 7.

The layer C is composed of an incompressible granular material renderedcoherent. This material is advantageously sand agglomerated by anysuitable plastic-type binder such as bitumen, rubberized binder or otherplastic material binder. By way of example, there can be used sandhaving a grain size of 0-5 mm. agglomerated by bitumen of grade 40-60. Arubber latex could also be used as the binder. The aforementionedindications are purely illustrative, since a large number ofcommercially available binders can be used, even sand having a differentgrain size. Similarly, although sand is preferred owing to its abundanceand low cost, granulated materials having similar properties could besubstituted therefor.

The interposed layer C results in a close contact between the plate Pand the face 2 of the bore, since when the nut 8 is screwed along therod this layer molds itself to the face 2 and fits around theasperities. Owing to its very nature the layer 2 wholly and uniformlytransmits all the pressures exerted thereon by the plate P.

Two methods are available for applying the layer C. The first method isthat shown in FIG. 2 and comprises applying the layer C when anchoringby spreading the agglomerated granular material over the saucer-shapedplate P. The other method is that shown in FIGS. 3-8 in which the layerC is previously applied on the anchorin-g plate with which itconstitutes a unit. This second method has the advantage for theoperator of not com-' FIG. 3 shows a saucer-shaped plate P having aprofile different to the late P and in which the layer C is applied bymolding. It will be noted that the passage 9a for the passage of the rod7 is more tapered than in the preceding embodiment and this precludesjamming of the threading of this rod.

FIG. 4 shows the plate illustrated in FIG. 3 placed in position, theupper face of the layer C, which was initially flat, having been causedto conform to the face 2 of the bore in the course of the screwing ofthe nut 8 along the rod 7.

FIG. 5 shows another type of saucer-shaped plate P whose layer C hasbeen previously applied on the plate. This permits providing at theupper end of the passage 9b a part-conical recess 11 forming a freespace for the flow of the material of which the layer C is composed.

The saucer-shaped plate P shown in FIG. 6 has a central portion '12in'the form of a hollow conical dome connected to the periphery of theplate by a pressed out intermediate portion 13. This arangement isadapted in the known manner to provide a controlled deformability of theplate P Further, it allows a suitable orientation of the anchoringdevice in the case of an inclined bore 3. To this end, a washer 14 isinserted in the dome 12 between the hole in the latter and the nut 8.This washer is capable of blocking itself in the dome in accordance withthe orientation of the rod relative to the axis of the hole 10 so as' toadapt itself to the inclination of the bore 3 relative to the face 2 ofthe ground. This presupposes that the rod 7 can itself take up aninclined position in the hole 10 which is provided large enough for thispurpose and the passage9c formed in the layer C above the hole 10 is ofsuitable section. The molding of the layer C on the requirement.

FIG. 7 shows a saucer-shaped plate P also permitting an orientation ofthe rod 7 in accordance with the inclina-' tion of the bore 3 which isshown greatly inclined relative to the face 2. The plate P comprises acentral hemispherical boss provided with a large slot 16 in a diametraldane. Disposed on the boss 15 is a washer 17 also hemispherical inshape, the boss 15 and the washer 17 constituting a swivel jointassembly. The passage 9d formed in the layer C in alignment with theslot 16 has a sufiicient extent to permit all the possible angularmovements of the rod 7 in the course of the swiveling of the latter.

FIG. 8 shows a saucer-shaped plate P also permitting a suitableorientation of the rod 7. The plate P comprises a central bearingportion 18 in which is rotatably mounted a cup 19 provided with a slot20 in a diametral plane. The nut bears on the cup 19 through the mediumof a curved washer 21. Here again, owing to the large possibilities oforientation afforded by the plate P the passage 9c has a great extent. I

The various possibilities of the method according to the invention willbe quite clear. While insuring a uniform distribution of the pressuresowing to its adaptation to the ground, the filling layer C does notinterfere in any way with the usual operation of the anchoring plates.

Apart from the adaptation of the anchoring face to the ground, the layerC affords various additional advantages. the bores 3 from the atmosphereof the galleries 1 which, especially in the case of marls, diminishesthedanger of swelling owing to entry of air. Moreover, the relativefluidtightness thus obtained precludes the trickling onto the platesoften observed at the present time. The corrosion of the plates isreduced owing to the interposition of the inert material of the layer Cbetween the roof and the plates.

Although specific embodiments of the invention have been described, manymodifications and changes may be plate P permits meeting the last Thusthis layer insulates the atmosphere of.

made therein without departing from the scope of the invention asdefined in the appended claims.

What is claimed is:

1. An anchoring device comprising a saucer-shaped anchoring plate havinga centural opening therein, an anchoring member extending through saidopening and adapted to engage in a ground-constituted roof to suspendsaid plate therefrom, said plate having a face in facing relation withthe ground-constituted roof, and a coherent, solid and plastic-typedeformable mass on said face of the plate, said mass being constitutedby an incompressible and non-deformable granular material and aplastic-type deformable binder in which the granular material isembeded, said mass having a thickness whereby to project from the platefor encountering and conforming to the contourof said roof andpreventing the plate from encountering the roof, said mass beinggenerally I shape retaining but being deformable under compression tothe extent permitted by compacting said non-deformable material, saidbinder being bitumen.

2. An anchoring device comprising a saucer-shaped anchoring plate havinga central opening therein, an anchoring member extending through saidopening and adapted to engage in a ground-constituted roof to suspendsaid plate therefrom, said plate having a face in facing relation withthe ground-constituted roof, and a coherent, solid and plastic-typedeformable mass on said face of the plate, said mass being constitutedby an incompressible and non-deformable granular material and aplastic-type deformable binder in which the granular material isembedded, said mass having a thickness whereby to project from the platefor encountering and conforming to the contour of said roof andpreventing the plate from encountering the roof, said mass beinggenerally shape retaining but being deformable under compression to theextent permitted by compacting said non-deformable material, said binderbeing a rubberized binder.

References Cited by the Examiner UNITED STATES PATENTS 1,817,033 8/1931Ross 94-182 2,000,978 5/1935 MOSClGY 94 1 2,603,573 7/1952 1310a l06281x 2,682,152 6/1954 Biel'el 61-45 2,748,594 6/1956 Edwards 61-453,086,421 4/1963 Hamman -1 FOREIGN PATENTS 924,624 3/1955 Germany.

842,078 7/1960 Great Britain. 1,222,640 6/1960 France.

CHARLES E. OCONNELL, Primary Examiner.

JACOB L. NACKENOFF, RICHARD W. COOKE, 111.,

FRANK L, ABBOTT, Examiners,

1. AN ANCHORING DEVICE COMPRISING A SAUCER-SHAPED ANCHORING PLATE HAVINGA CENTRAL OPENING THEREIN, AN ANCHORING MEMBER EXTENDING THROUGH SAIDOPENING AND ADAPTED TO ENGAGE IN A GROUND-CONSTITUTED ROOF TO SUSPENDSAID PLATE THEREFROM, SAID PLATE HAVING A FACE IN FACING RELATION WITHTHE GROUND-CONSTITUTED ROOF, AND A COHERENT, SOLID AND PLASTIC-TYPEDEFORMABLE MASS ON SAID FACE OF THE PLATE, SAID MASS BEING CONSTITUTEDBY AN INCOMPRESSIBLE AND NON-DEFORMABLE GRANULAR MATERIAL AND APLASTIC-TYPE DEFORMABLE BINDER IN WHICH THE GRANULAR MATERIAL INEMBEDDED, SAID MASS HAVING A THICKNESS WHEREBY TO PROJECT FROM THE PLATEFOR ENCOUNTERING AND CONFORMING TO THE CONTOUR OF SAID ROOF ANDPREVENTING THE PLATE FROM ENCOUNTERING THE ROOF, SAID MASS BEINGGENERALLY SHAPE RETAINING BUT BEING DEFORMABLE UNDER COMPRESSION TO THEEXTENT PREMITTED BY COMPACTING SAID NON-DEFORMABLE MATERIAL, SAID BINDERBEING BITUMEN.